Since 1979, the leaders of the Islamic Republic of Iran have said many despicable things about the state of Israel, including that they want to see what they call a “cancer” removed from the Middle East. They repeat a now familiar litany of abuse composed of a mix of Nazi propaganda, Islamist ideology, and a peculiarly Iranian vision of world domination. The convergence of this torrent of abuse with Iran’s desire to possess nuclear weapons has led many observers, including myself, to fear that we are facing the specter of a second Holocaust. We do not do so because we are pessimists by nature nor because we make simplistic comparisons between the Nazi years and our own. Rather, we take that view because we see sufficient similarities between the years preceding the Holocaust and our own time to err on the side of pessimism. Now as then a medium-sized power undergoing processes of rapid modernization has brought forth a powerful movement that embraces modernity’s technology, rejects its liberal values, and aims its hatred at the United States, the Jews, and, yes, the Communists as well.

Yet in Washington and the capitals of Europe, and even by some former officials of Israel’s intelligence service, we are told that our fears are misplaced and even a bit hysterical because, after all, the Iranians have a state and, like all state powers, care about their own survival. Yes, the Iranians say hateful and absurd things about the Great Satan and the Little Satan, but the optimists in Washington argued that these absurdities compete with a capacity for rationality and cost-benefit analysis that other nuclear powers in the past displayed. The Iran debate has never been about Right and Left in any conventional sense of those terms. It has been about whether the leaders of the United States government actually believe that the Iranian leaders believe what they say again and again, or whether our leaders assume Iran’s rulers are as cynical and, in the narrow sense of the term, as rational as all other leaders who understand that using nuclear weapons brings with it a very high risk of committing national suicide. At its core, the debate about Iran is one about how we interpret the core beliefs of the Iranian regime and whether we take these ideas seriously as its guides to policy.

Hitler is dead. Nazi Germany is gone. We can rest assured that “never again” will Hitler destroy two-thirds of the Jews of Europe. The issue is whether the Iranian regime will use nuclear weapons in the future to attack the state of Israel and, for that matter, perhaps the United States as well—for in modern history those who hate the Jews also, always, despise the United States. Yet in the face of these dire prospects, many of the same intellectuals and policymakers who express pessimism about irreversible climate change due to human activity, oppose nuclear power because it is, in their view, too dangerous, and consider economic globalization to be more a curse than a blessing turn into remarkable optimists when it comes to Iran and the bomb. They call their optimism “realism” and assume that things will turn out just fine unless the United States does something “stupid” like use its military power to destroy Iran’s nuclear facilities or intensify economic sanctions unless Iran agrees to a deal that permits “anywhere, anytime” inspections.

Though Hitler is dead and Nazi Germany is gone the problem of underestimating the role of ideology in politics remains very much with us. A few key facts about what Hitler and the Nazis said and how the Allies responded bear repeating. First, on numerous occasions beginning in 1939, Hitler publicly announced that he intended to “exterminate the Jewish race in Europe.” He made the German nouns for extermination and annihilation (Vernichtung and Ausrottung) world-famous. Contrary to some conventional wisdom, he did not keep his policies about the Jews secret, nor did he speak in euphemisms. He spoke bluntly and often about his intention to exterminate the Jews. As is well known, on January 30, 1939 Hitler first made what he called a prophecy about what would happen if a political subject he called “international Jewry…once again” pushed the world into war. The result he said then would be “the extermination of the Jewish race in Europe.” On January 30, 1941 in a speech to the Reichstag he repeated a version of the prophecy and predicted that “the role of Jewry in Europe would be finished…Today, they [the Jews] may still be laughing about [that statement], just as they laughed about my earlier prophecies.” Yet Hitler claimed that “now our racial knowledge is spreading from people to people” which offered hope that “those who are still our antagonists will one day recognize the greater domestic enemy and will then make common cause with us: against the international Jewish exploitation and corruption of nations!”

The following day, The New York Times lead editorial “When Hitler Threatens” illustrated the difficulty its editors were having in taking Hitler’s ideas seriously. It offered a classic example of the realist temper. They wrote that

We know now that the editors of the Times were mistaken. Hitler kept many of his promises and fulfilled many of his threats. I cite the Times editorial because the habits of thinking and the definition of political sophistication evident in “When Hitler Threatens” remain part of our political and intellectual world today. Yet why did some of the most intelligent, well-informed, and sophisticated observers make such a blunder? Why, for example, did Franz Neumann, the director of the Division of Research and Analysis in the U.S. Government’s Office of Strategic Services write in his 1944 work Behemoth: The Structure and Practice of National Socialism that the Nazis would not kill the Jews because they needed them as a scapegoat onto which they could divert the frustrations caused by capitalism? Why, for that matter, did Neville Chamberlain think Hitler could be appeased with the license to gobble up German-speaking territories? Why did Stalin believe that Hitler would uphold the terms of the non-aggression pact he had signed with him in 1939 and thus not invade the Soviet Union in 1941? Conversely, why was Winston Churchill right about Hitler’s intentions when so many other people were wrong?

In the mid-1970s, the German historian Karl Dietrich Bracher famously wrote that the history of National Socialism had been the history of its underestimation, an underestimation that was common across the political spectrum in the last years of the Weimar Republic and then appeared again in the era of appeasement and the non-aggression pact. The cause of these failures of interpretation lay deep in the heart of our intellectual traditions and in a conventional understanding of what it means to be a sophisticated observer of history and politics. In the Western tradition as reflected in the writings of Thucydides, Niccolo Machiavelli, Thomas Hobbes, and Karl Marx, among others, sophistication or “realism” about the ways of the world means the refusal to take the ideas of others seriously as guides to their actions. It means viewing the ideas of others as tools, instruments, techniques, and methods in the service of other unstated but actually far more fundamental purposes. For the realist and sophisticate in this sense, to take the ideas of others seriously, especially when these ideas offend our understanding of common sense, is a sign of naivety and gullibility. Marx told us that ideas were actually mere ideology masking class interest. Hobbes and realist thinkers in international politics dismissed ideological statements as mere fluff compared to the presumably obvious definition of national interests. For the post-Marxist left, the French historian Michel Foucault suggested that all ideas were rationalizations about the preservation of power, especially power of presumably repressive Western societies. Politicians in a liberal democracy accustomed to the peaceful cynicism that is the fuel of parliamentary and congressional compromises seem rarely to have met a fanatic who will walk away from a good deal. The cynicism both of theory and of practice in our traditions inclines us to not take the views of fanatics seriously.

These core elements of the Western political tradition contributed to making the history of National Socialism, in part, the history of its underestimation and of the dismissal of its vocally expressed ideas. To take Hitler’s ideas seriously, to believe that he would make good on his threats, was to sound unsophisticated and to arouse the suspicion that one was a gullible fool willing to believe that men like Hitler could actually believe the nonsense they uttered. Churchill, you will recall, was dismissed as a man of the 19^th century—a romantic, unsophisticated, not fully modern man—precisely because he took Hitler’s threats seriously.

Among intellectual and political historians of modern Europe of the generation preceding my own, including scholars such as George Mosse, François Furet, Saul Friedlander and Karl Bracher, a different view of these issues emerged. Both their generation and mine, their heirs and successors, view the dismissal of the causal import of ideas in politics as what we call a “rationalist bias.” By that we do not mean a bias in favor of reason but rather a bias in favor of the idea that human beings are fundamentally rational in the sense in which that term is understood in modern economics: that their preeminent desire is to survive and prosper—to be happy, healthy, and enjoy full, long lives. Thus, when fanatics assert that, despite all evidence to the contrary, Jews run the world, or when they proudly declare that they love death more than life, the inclination of students educated in powerful currents of Western thinking leads many to insist that these fanatics can’t possibly believe such rubbish. We historians have argued that, especially in view of the events of Europe’s 20^th century, such underestimation of the role of ideology rests on an untenably optimistic understanding of human nature. It neglects Freud’s understanding of the conscious and unconscious wishes that lead people to believe in illusions of various sorts. From a historian’s longer-term perspective, it ignores the variety of deeply held religious beliefs that exerted profound influence on politics from the wars of religion of the 17^th century to the wars of secular religion of the 20^th—and now again in our time, when religious fanaticism is again ascendant.

Seen from the perspective of this journey through some conceptual issues that concern historians of German history, the tension between President Barack Obama and Prime Minister Benjamin Netanyahu does replicate the debates of the 1930s when the cool rationalists thought Hitler could be contained and appeased while the emotional Churchill sounded like a voice from a less-sophisticated era. The President, a product of our country’s elite intellectual institutions, finds the ideology of the Iranian regime repellent, yet does not believe it stands in the way of rationality as he understands it. The Prime Minister, evoking Churchill at many opportunities, takes the Iranians at their word when they say publicly that they want to destroy the state of Israel. The New York Times today sides with the President in the same spirit of apparent sophistication and worldliness with which it expressed skepticism that Hitler would make good on his threats.

One of the most remarkable aspects of the rise of the various permutations of radical Islam that evoke memories of Nazism is that like the Nazis, the Islamists publicly declare their murderous intentions for all to hear. It is not necessary to risk life and limb in order to print English translations of Ayatollah Khamenei’s statements to his followers or accurate summaries of the Hamas Charter of 1988. The documents are readily available on numerous websites. Yet, like the very famous and very public texts by Hitler and Goebbels, they are too rarely subject to close textual interpretation. Like the speeches of Hitler and the essays of Goebbels, the truth of their intention is hiding in plain sight. So it was that in 2006, when I published The Jewish Enemy: Nazi Propaganda during World War II and the Holocaust, that the close reading of some famous texts came as news to fellow scholars and general readers alike. That work sought to advance our knowledge by elaborating the Nazis’ anti-Semitic interpretation of World War II as a “Jewish war” begun and escalated by an international Jewish conspiracy rooted in Washington, London, and Moscow whose purpose supposedly lay in the extermination of the German people. The Nazi response was to present the murder of the Jews as an act of self-defense.

My elaboration of the Nazis’ interpretation of World War II was received in the profession as an important addition to our knowledge about the Third Reich. Historians had previously paid little attention to Hitler’s repetition of the famous prophecy and Joseph Goebbels’ public announcement that the Jews were, in November 1941, “now suffering a gradual extermination which they had intended for us.” New as well as a subject of scholarship were the wall posters distributed on a weekly basis all over Germany, many of which repeated Hitler’s public determination to exterminate the Jews of Europe. The truth about Hitler’s determination to murder the Jews of Europe had been hiding in plain sight for seven decades while many scholars had turned their attention elsewhere. Perhaps the rationalist bias, the conviction that Hitler did not really mean what he said in public, had discouraged closer examination of what he and others had said about what they were planning and, once it was underway, why they were in the process of murdering the Jews of Europe.

Though Nazism was defeated, the anti-Semitic impulse persisted, most blatantly in the traditions of Islamism. In addition, for most of the Cold War, the Soviet Union and its allies waged an international campaign against “Zionism and imperialism” which amounted to an effort to damage the moral legitimacy of Israel and aid those seeking to destroy it by force of arms. In part, our current era’s addiction to euphemism and refusal to speak frankly about radical anti-Semitism in Islamist form are the gifts of the Communists and radical left of the Cold War era to Islamic radicals, their successors in hatred. The political warfare of the secular left in those years softened up the West and weakened its defenses. It is an irony that despite the West’s victory in the Cold War, it became possible for the most reactionary of ideas to find shelter under the protective umbrella of leftist anti-imperialism and more recently behind accusations of racism or advocacy of “Islamophobia.” The result is a central irony of recent years, namely that, with important exceptions, it is the political center and right, more than liberals and leftists, who have led the criticism of Islamist ideology, a set of ideas that bears closer similarity to Nazism and fascism than to Communism.

Taking the ideas of others seriously, especially when we find those ideas repugnant, is not an expression of racism or Islamophobia. On the contrary, it manifests our desire to treat everyone involved in politics equally and to avoid the condescension inherent in the belief that others don’t really mean what they say or that we should not pay close attention to exactly what it is they are saying. Understanding why an actor acts is not synonymous with empathizing or agreeing with his or her beliefs. It is rather to acknowledge rightfully that others, our enemies as well as our friends, have beliefs that guide actions. Hitler was exceptional in many ways but he was not unusual in history in acting on the basis of firmly held beliefs. Previous generations found it hard to take those absurdities with the seriousness they deserved. We have no excuse for repeating their blunders or for reassuring ourselves optimistically that things will turn out for the best.